Question 1

Most astronomical objects emit light over a broad range of wavelengths.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is not one of the three main categories of observation generally used by astronomers?

Accepted Answer

A) filtering to look at just a single color from an object 
B) timing to track how an object's brightness varies with time 
C) spectroscopy to spread an object's light into a spectrum 
D) imaging to get a picture of an astronomical objects 
A) filtering to look at just a single color from an object 
B) timing to track how an object's brightness varies with time 
C) spectroscopy to spread an object's light into a spectrum 
D) imaging to get a picture of an astronomical objects

Question 3

The angular resolution of a telescope is never less than its diffraction limit.

Accepted Answer

A) True 
 B)False

Question 4

Suppose the two headlights on a car are separated by 1 meter and you are looking at the car from a distance of 2 kilometers.What is the angular separation of the headlights? Can your eyes resolve the two headlights?
(Hint: Recall the angular separation formula α = $ \frac{\mathrm{s}}{2 \pi \mathrm{d}} $ × 360°;the angular resolution of the human eye is about 0.020°. )

Accepted Answer

The separation of the headlights is s =

Question 5

What is the purpose of interferometry?

Accepted Answer

A) It allows two or more small telescopes to achieve the angular resolution of a much larger telescope. 
B) It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently. 
C) It is designed to prevent light pollution from interfering with astronomical observations. 
D) It reduces the twinkling of stars caused by atmospheric turbulence. 
A) It allows two or more small telescopes to achieve the angular resolution of a much larger telescope. 
B) It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently. 
C) It is designed to prevent light pollution from interfering with astronomical observations. 
D) It reduces the twinkling of stars caused by atmospheric turbulence.

Question 6

Which of the following best describes the principle advantage of CCDs over photographic film?

Accepted Answer

A) CCDs allow long exposures (e.g. ,minutes or hours)and film does not. 
B) CCDs capture a much higher percentage of the incoming photons than film. 
C) CCDs can record the colors of astronomical objects accurately while film cannot. 
D) CCDs can be attached to modern telescopes more easily than can photographic film. 
A) CCDs allow long exposures (e.g. ,minutes or hours)and film does not. 
B) CCDs capture a much higher percentage of the incoming photons than film. 
C) CCDs can record the colors of astronomical objects accurately while film cannot. 
D) CCDs can be attached to modern telescopes more easily than can photographic film.

Question 7

Suppose you point your telescope at a distant object.Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?

Accepted Answer

A) The photograph will have far better angular resolution than you can see with your eye. 
B) By using a long exposure time,the photograph can allow you to see objects that would be too dim to see with your eye. 
C) If taken with a camera with a sensitive detector such as a CCD,the photograph can capture a much larger percentage of the incoming photons than can your eye. 
D) The photograph provides a more reliable record of what is seen through the telescope than can a drawing made by eye. 
A) The photograph will have far better angular resolution than you can see with your eye. 
B) By using a long exposure time,the photograph can allow you to see objects that would be too dim to see with your eye. 
C) If taken with a camera with a sensitive detector such as a CCD,the photograph can capture a much larger percentage of the incoming photons than can your eye. 
D) The photograph provides a more reliable record of what is seen through the telescope than can a drawing made by eye.

Question 8

Which of the following statements best describes the two principal advantages of telescopes over eyes?

Accepted Answer

A) Telescopes can collect far more light with far better angular resolution. 
B) Telescopes can collect far more light with far greater magnification. 
C) Telescopes have much more magnification and better angular resolution. 
D) Telescopes collect more light and are unaffected by twinkling. 
E) Telescopes can see farther without image distortion and can record more accurate colors. 
A) Telescopes can collect far more light with far better angular resolution. 
B) Telescopes can collect far more light with far greater magnification. 
C) Telescopes have much more magnification and better angular resolution. 
D) Telescopes collect more light and are unaffected by twinkling. 
E) Telescopes can see farther without image distortion and can record more accurate colors.

Question 9

Which of the following studies is best suited to astronomical observations that fall into the category called timing?

Accepted Answer

A) studying how different planets differ in their surface compositions 
B) studying how a star's brightness varies over a period of 3 years 
C) measuring the rotation rate of a distant star 
D) determining the age of the solar system 
A) studying how different planets differ in their surface compositions 
B) studying how a star's brightness varies over a period of 3 years 
C) measuring the rotation rate of a distant star 
D) determining the age of the solar system

Question 10

The largest effective telescope,created by radio interferometry,is the size of

Accepted Answer

A) several football fields,in a natural depression in Puerto Rico. 
B) tens of miles across,in the deserts of New Mexico. 
C) the state of New Mexico. 
D) the continental United States. 
E) Earth. 
A) several football fields,in a natural depression in Puerto Rico. 
B) tens of miles across,in the deserts of New Mexico. 
C) the state of New Mexico. 
D) the continental United States. 
E) Earth.

Question 11

Which of the following studies is best suited to a time monitoring experiment?

Accepted Answer

A) studying how different stars differ in their chemical compositions 
B) studying whether a particular star's brightness is steady or variable 
C) determining the age of the solar system 
D) measuring the rotation rate of a distant star 
E) estimating the time since the Big Bang 
A) studying how different stars differ in their chemical compositions 
B) studying whether a particular star's brightness is steady or variable 
C) determining the age of the solar system 
D) measuring the rotation rate of a distant star 
E) estimating the time since the Big Bang

Question 12

The Hubble Space Telescope is famous because,at least at the time of its launch,it was the largest visible light telescope ever built.

Accepted Answer

A) True 
 B)False

Question 13

What causes stars to twinkle?

Accepted Answer

A) It is intrinsic to the stars-their brightness varies as they expand and contract. 
B) variations in the absorption of the atmosphere 
C) variable absorption by interstellar gas along the line of sight to the star 
D) bending of light rays by turbulent layers in the atmosphere 
E) the inability of the human eye to see faint objects 
A) It is intrinsic to the stars-their brightness varies as they expand and contract. 
B) variations in the absorption of the atmosphere 
C) variable absorption by interstellar gas along the line of sight to the star 
D) bending of light rays by turbulent layers in the atmosphere 
E) the inability of the human eye to see faint objects

Question 14

What does angular resolution measure?

Accepted Answer

A) the angular size of the smallest features that the telescope can see 
B) the brightness of an image 
C) the size of an image 
D) the number of electromagnetic waves captured by an image 
A) the angular size of the smallest features that the telescope can see 
B) the brightness of an image 
C) the size of an image 
D) the number of electromagnetic waves captured by an image

Question 15

Which of the following best describes what we mean by the focal plane of a telescope?

Accepted Answer

A) It is the upper surface of the telescope's primary lens or mirror. 
B) It is the place where,if we mounted film or an electronic detector,we could get a clear (not blurry)image of an object viewed through the telescope. 
C) It is the lower surface of the telescope's primary lens or mirror. 
D) It is the surface of the lens on the eyepiece,through which you would look to see objects in the telescope's field of view. 
A) It is the upper surface of the telescope's primary lens or mirror. 
B) It is the place where,if we mounted film or an electronic detector,we could get a clear (not blurry)image of an object viewed through the telescope. 
C) It is the lower surface of the telescope's primary lens or mirror. 
D) It is the surface of the lens on the eyepiece,through which you would look to see objects in the telescope's field of view.

Question 16

What does the technique of interferometry allow?

Accepted Answer

A) It allows two or more telescopes to obtain a total light-collecting area much larger than the total light-collecting area of the individual telescopes. 
B) It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes. 
C) It allows us to determine the chemical composition of stars. 
D) It allows astronomers to make astronomical observations without interference from light pollution. 
E) It allows the same telescope to make images with both radio waves and visible light. 
A) It allows two or more telescopes to obtain a total light-collecting area much larger than the total light-collecting area of the individual telescopes. 
B) It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes. 
C) It allows us to determine the chemical composition of stars. 
D) It allows astronomers to make astronomical observations without interference from light pollution. 
E) It allows the same telescope to make images with both radio waves and visible light.

Question 17

Which of the following effects is caused by atmospheric turbulence?

Accepted Answer

A) twinkling of stars 
B) light pollution 
C) magnification of images 
D) diffraction of light 
A) twinkling of stars 
B) light pollution 
C) magnification of images 
D) diffraction of light

Question 18

Suppose the angular separation of two stars is smaller than the angular resolution of your eyes.How will the stars appear to your eyes?

Accepted Answer

A) You will not be able to see these two stars at all. 
B) The two stars will look like a single point of light. 
C) The two stars will appear to be touching,looking rather like a small dumbbell. 
D) You will see two distinct stars. 
E) You will see only the larger of the two stars,not the smaller one. 
A) You will not be able to see these two stars at all. 
B) The two stars will look like a single point of light. 
C) The two stars will appear to be touching,looking rather like a small dumbbell. 
D) You will see two distinct stars. 
E) You will see only the larger of the two stars,not the smaller one.

Question 19

The diffraction-limited resolution of a 10-meter telescope is about 0.01 arcsecond for visible light.Would you expect the actual angular resolution of a Keck 10-meter telescope in Hawaii to be better than,equal to,or worse than 0.01 arcsecond? Explain.

Accepted Answer

It would be worse th

Question 20

What is spectral resolution? Why can a large telescope allow for a higher spectral resolution than a smaller telescope?

Accepted Answer

Spectral resolution is a measure of the

Exam 6: Telescopes: Portals of Discovery

Most astronomical objects emit light over a broad range of wavelengths.

Which of the following is not one of the three main categories of observation generally used by astronomers?

The angular resolution of a telescope is never less than its diffraction limit.

What is the purpose of interferometry?

Which of the following best describes the principle advantage of CCDs over photographic film?

Suppose you point your telescope at a distant object.Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?

Which of the following statements best describes the two principal advantages of telescopes over eyes?

Which of the following studies is best suited to astronomical observations that fall into the category called timing?

The largest effective telescope,created by radio interferometry,is the size of

Which of the following studies is best suited to a time monitoring experiment?

The Hubble Space Telescope is famous because,at least at the time of its launch,it was the largest visible light telescope ever built.

What causes stars to twinkle?

What does angular resolution measure?

Which of the following best describes what we mean by the focal plane of a telescope?

What does the technique of interferometry allow?

Which of the following effects is caused by atmospheric turbulence?

Suppose the angular separation of two stars is smaller than the angular resolution of your eyes.How will the stars appear to your eyes?

The diffraction-limited resolution of a 10-meter telescope is about 0.01 arcsecond for visible light.Would you expect the actual angular resolution of a Keck 10-meter telescope in Hawaii to be better than,equal to,or worse than 0.01 arcsecond? Explain.

What is spectral resolution? Why can a large telescope allow for a higher spectral resolution than a smaller telescope?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters